wtw SenTix ORP 900 Operating instructions

Brand: wtw

Model: SenTix ORP 900

Type: Operating instructions

This manual is also suitable for

SenTix ORP-T 900

OPERATION MANUAL

ba75845e02 12/2014

SenTix

PH-MESSKETTE MIT FLÜSSIG-REFERENZSYSTEM UND SCHLIFFDIAPHRAGMA

SenTix

ORP 900

SenTix

ORP-T 900

OPERATING MANUAL

2 ba75845e02 12/2014

SenTix

ORP 900

Reprinting - even as excerpts - is only allowed with the explicit written

authorization of WTW GmbH, Weilheim.

Printed in Germany.

For the most recent version of the manual, please visit

<hyperlink>www.WTW.com

SenTix

General information

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General information

Automatic sensor

recognition

The sensor electronics with the stored sensor data is in the connecting head

of the electrode. The data include, among other things, the sensor type and

series number. The data is recalled by the meter when the sensor is

connected and is used for measurement and for measured value documen-

tation.

The digital transmission technique guarantees the failure-free communi-

cation with the meter even with long connection cables. If the sensor firmware

is enhanced by WTW, it can be updated via the meter.

Technical data

General data Reference electrolyte 3 mol/l KCl, Ag

free

Junction Ceramic

Electrode material and shape Platinum / circle

Measurement and

application

characteristics

mV measuring range - 1250.0 ... + 1250.0

Allowed temperature range 0 ... 100 °C (32 ... 212 °F)

Typical application Laboratory

Shaft dimensions,

material, electrical

connection

Shaft length 120 mm

Shaft diameter 12 mm

Shaft material Glass

Combination electrode con-

nection

Fixed cable

Meter connection Digital plug

Connection cable Length 1.5 m

Diameter 4.3 mm

Smallest allowed bend

radius

Fixed installation: 20 mm

Flexible use: 60 mm

Plug type Socket, 4 pins

Accuracy of the

IDS measuring

technique

Measured parameter Accuracy (± 1 digit)

U [mV] ± 0.2

T [°C] (SenTix

ORP-T 900) ± 0,1

Commissioning, measuring, checking SenTix

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Commissioning, measuring, checking

Commissioning Prepare the electrode for measuring as follows:

 Open the refilling opening for the reference electrolyte solution. Depend-

ing on the model, the stopper of the refilling opening is an elastomer stop-

per or a slider.

The refilling opening must always be open during measurement!

 Remove the watering cap from the electrode tip. Possible salt deposits in

the area of the watering cap do not affect the measuring characteristics

and can easily be removed with deionized water.

 Connect the combination electrode to the meter.

 Measure with the electrode according to the operating manual of the meter

and observe the following rules while doing so:

General rules for

measuring

 Make sure the refilling opening for the reference electrolyte solution is

open.

 Avoid the carryover of sample solution from one measurement to the next

as follows:

– Shortly rinse the sample beakers with the solution the beakers are to

be filled with next.

– Between measurements, rinse the electrode with the solution that fol-

lows. Alternatively, you can also rinse the electrode with deionized wa-

ter and then carefully dab it dry.

 Immerse the electrode in the solution in a vertical or slightly tilted position.

 Make sure the immersion depth is correct. The junction must be complete-

ly submersed in the solution. The junction is in the area of the bottom end

For ORP electrodes with platinum electrode, please follow the

instructions in section A

CTIVATING PLATINUM ELECTRODES.

Please keep the watering cap. It is required for the electrode to

be stored. Always keep the watering cap clean.

Refilling

opening

SenTix

is temperature dependent and can be taken from the following tableStorage

ba75845e02 12/2014

of the shaft (see arrow).

At the same time, the level of the reference electrolyte must be at least 2

cm above the level of the solution.

Conversion to

normal hydrogen

electrode

= U

Meas

+ U

Ref

is temperature dependent and can be taken from the following table (see

also DIN 38404-6):

is temperature dependent and can be taken from the following table

Stor-

age

During short

measuring breaks

Immerse the electrode in the reference electrolyte with the refilling opening

open.

SenTix

ORP 900

with: U

= ORP, referring to the normal hydrogen electrode

Meas

= Measured ORP

Ref

= Voltage of the reference system compared to the normal

hydrogen electrode

T (°C) T (°F) U

Ref

[mV] T (°C) T (°F) U

Ref

[mV]

SenTix

ORP 900 SenTix

ORP 900

0 32 +224 35 95 +200

5 41 +221 40 104 +196

10 50 +217 45 113 +192

15 59 +214 50 122 +188

20 68 +211 55 131 +184

25 77 +207 60 140 +180

30 86 +203

Aging SenTix

ba75845e02 12/2014

Prior to the next measurement, shortly rinse the electrode with the test

sample or deionized water.

Overnight or

longer

Insert the clean electrode into the watering cap filled with reference

electrolyte and shut the refilling opening.

Aging

Every ORP electrode undergoes a natural aging process. Extreme operating

conditions can considerably shorten the lifetime of the electrode. These are:

 Strong acids or lyes, hydrofluoric acid, organic solvents, oils, fats, bro-

mides, sulfides, iodides, proteins

 High temperatures

 High changes in pH and temperature.

The warranty does not cover failure caused by measuring conditions and

mechanical damage.

Maintenance and cleaning

During operation, a small amount of reference electrolyte leaks through the

junction from the electrode into the test sample. If the level of reference

electrolyte becomes too low with time, refill it through the refilling opening.

Refilling the

reference

electrolyte

Refilling is very easy using a dropping bottle. Proceed as follows:

 Cut off the tip of the dropping bottle at a right angle until the opening in the

tip can be seen

 Open the refilling opening of the electrode

 Press the tip of the dropping bottle into the refilling opening while turning

it slightly

 Pump several small quantities of the reference electrolyte into the stem

using the dropper bottle

Electrode Reference electrolyte Model

(see page 8)

SenTix

ORP 900 3 mol/l KCl, Ag

-free KCl-250 (250 ml)

SenTix

ORP-T 900

During longer storing periods, salt sediments may develop on the

watering cap. They do not affect the measuring characteristics

and can easily be removed with deionized water when the elec-

trode is put into operation again.

SenTix

Activating platinum electrodes

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 Pull the dropping bottle out of the refilling opening while turning it slightly

as necessary.

Cleaning Remove water-soluble contamination by rinsing with deionized water. Re-

move other contamination as follows:

After cleaning Rinse the electrode with deionized water.

Activating platinum electrodes

First-time

activation during

installation and as

required

For first-time activation use the activation powder from the SORT/RH reagent

set (component of the SORT/RH reagent set). Immerse the moist (but not

dripping) platinum electrode into the activation powder and rotate the

electrode several times in the powder. Then remove the activation powder

under flowing water with a soft brush (e.g. toothbrush).

Activation during

very long set-up

times

When changing from oxidizing to reducing test solutions and vice versa this

can result in set-up times that can take significantly more than an hour. In this

case pretreatment (activation) of the platinum surface can shorten the set-up

time. The type of pretreatment (reducing or oxidizing) is based on the pH val-

ue and the ORP voltage (U

) of the test solution where the latter must be es-

timated for the first measurement.

Contamination Cleaning procedure

Fat and oil Rinse with water containing household wash-

ing-up liquid

Lime and hydroxide deposits Rinse with citric acid (10 % by weight)

Protein Immerse in pepsin cleaning solution PEP/pH

for approx. 1 hour.

Note:

Make sure the level of the reference

electrolyte is above that of the cleaning solu-

tion.

Wear parts and accessories SenTix

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The type of pretreatment can then be determined using the following diagram

where U

is based on the normal hydrogen electrode:

Wear parts and accessories

Oxidizing pretreat-

ment

Immerse the platinum electrode for two to three

days in a sulfuric acid clorina solution (0,5 g clorina

powder, 100 ml H

O dist., 2-3 ml 20% sulfuric acid).

Clorina powder for producing the solution is includ-

ed in the SORT/RH reagent set.

Note:

The diaphragm must not be immersed in the

clorina solution!

Reducing pretreat-

ment

When the electrode is ready for the test immerse it

in the RH 28 ORP buffer solution and wait for a sta-

ble measured value.

Detailed information on activating platinum electrodes, such as

how to produce the clorina solution, is given in the WTW applica-

tion report entitled R

EGENERATING ORP ELECTRODES. The appli-

cation report is included in the SORT/RH reagent set.

1000

800

600

400

200

20481012146

pH value

in mV

oxidizing pretreatment

reducing pretreatment

Description Model Order no.

Reference electrolyte solution 3 mol/l KCl,

free (250 ml)

KCl-250 109 705

Reagent set for regenerating ORP platinum

electrodes, consisting of 10 g activation pow-

der and 30 g clorina powder

SORT/RH 109 730

ORP buffer solution for checking ORP

electrodes U

= 427 mV, bottle of 250 ml

RH 28 109 740

SenTix

Wear parts and accessories

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Pepsin cleaning solution, 3 bottles of 250 ml

each

PEP/pH 109 648

Wear parts and accessories SenTix

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Wissenschaftlich-Technische

Werkstätten GmbH

Dr.-Karl-Slevogt-Straße 1

D-82362 Weilheim

Germany

+49 881 183-0

+49 881 183-420

info@wtw.com

www.wtw.com

Tel:

Fax:

E-Mail:

Internet:

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wtw SenTix ORP 900 Operating instructions

Brand: wtw

Model: SenTix ORP 900

Type: Operating instructions

This manual is also suitable for

SenTix ORP-T 900

Download PDF

report

wtw SenTix ORP 900 Operating instructions

This manual is also suitable for

wtw SenTix ORP 900 Operating instructions

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